In the prior art, a map database such as a CD or DVD storing road map data used for a navigation unit which carries out routing assistance or such, and a system for updating control data of a vehicle, are known (for example, see a patent document 1). By this system, it is possible to respond to a temporal change in the map data, thus it is possible to prevent routing assistance or such from being carried out according to original old map data, as much as possible. Further, since it is possible to carry out appropriate assistance control according to a unique position of each vehicle, it is possible to prevent optimum assistance control from not being carried out.    Patent Document 1: Japanese Laid-Open Patent Application No. 10-181482